Carb or brake cleaner works well. Dry with compressed air. THEN....a healthy dose of Hornady One Shot, shake out excess, and let dry. This is the ONLY thing I use One Shot for (commonly referred to One Case Stuck).

For your brass, start buying ZipLoc brand gallon bags, and store all of your brass in them. You will still have some minor change in color due to temperature variation.

Another trick, store powder, primers, brass, loaded ammo....in a non operating refrigerator or freezer. These actually help to control temps due to the insulation. Don't store your powder and primers together please. :)